If so, you will want to find some older cdr's that are rated for 1x/2x/4x etc.
Slow burn speeds mean the laser puts out less energy, but over a greater amount of time.
Fast burn speeds mean the laser puts out more energy over a smaller amount of time.
The chemicals in your cdr disc likely will not burn correctly with less energy coming from the laser, and your resulting disc will probably be a coaster.
Nero 6 does support those burn speeds, and so does many of the newer drives, I've got some old 4x cdr/w discs that still work in my new DL DVD-R drive.